Lithium battery pack with improved tab packaging position

Abstract

The utility model discloses a lithium battery pack with an improved tab packaging position, which relates to the technical field of lithium batteries and comprises a battery cell, a protective film is wrapped outside the battery cell, a packaging edge is arranged at one end of the protective film, and a tab is packaged on the packaging edge; the tab comprises an aluminum strip electrically connected with the battery cell, a nickel strip is welded at one end of the aluminum strip, so that an overlapping region is formed at the welding part of the aluminum strip and the nickel strip, two sides of the exterior of the overlapping region are respectively coated with a layer of tab glue, and the two layers of tab glue are mutually adhered; the packaging edge is further provided with an upper clamping plate and a lower clamping plate, the upper clamping plate and the lower clamping plate are arranged on the two sides of the packaging edge respectively and spliced with each other to apply clamping force to the packaging edge, and an overlapping area generated by welding of an aluminum strip and a nickel strip is wrapped with two layers of tab glue, so that the phenomenon that a protective film is punctured by defects caused by a step structure of the overlapping area is avoided; and the upper clamping plate and the lower clamping plate are used for applying clamping force to the packaging edge, so that the packaging edge is tighter, the tightness between the packaging edge and the ear glue is improved, and electrolyte leakage is avoided.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a lithium battery pack with an improved tab packaging position. Background Technology

[0002] Lithium-ion battery packs, also known as pouch lithium batteries, typically refer to lithium batteries encapsulated in an aluminum-plastic composite film casing. Due to their advantages such as light weight, lower mold costs, and higher safety, their market share is gradually expanding.

[0003] The tabs are components of the battery circuit, and are metallic conductors that lead the positive and negative electrodes out of the cell. They are one of the most important raw materials for lithium batteries. The tabs are divided into positive and negative electrodes. The negative electrode tabs are generally made of nickel strips, while the positive electrode tabs are generally made of aluminum strips. In the production process of the positive electrode tabs, in order to facilitate the welding of the positive electrode tabs to copper foil, a section of nickel strip is usually laser-welded onto the aluminum strip outside the lithium battery body. This type of tab is called an aluminum-to-nickel tab.

[0004] In existing technologies, to avoid excessively long tabs, a technique has been developed that uses aluminum strip to wrap the tab adhesive, and then welds the nickel strip to the aluminum strip near the tab adhesive. However, when welding aluminum to nickel tabs, the aluminum strip and nickel strip need to overlap each other, forming a stepped structure. The presence of this stepped structure poses a risk that the outer aluminum-plastic film may be punctured by the stepped structure when the lithium battery is packaged with tabs, which in turn leads to the risk of electrolyte leakage inside the lithium battery.

[0005] Meanwhile, in the current encapsulation of electrode tabs, the sealing effect is mainly achieved by bonding the electrode tab adhesive to the aluminum-plastic film of the battery pack through heat fusion during the encapsulation process. However, if the temperature control is deviated during the heat fusion sealing of the electrode tab adhesive and the aluminum-plastic film, it can easily lead to local over-melting or incomplete fusion, which affects the sealing and firmness and causes electrolyte leakage. Furthermore, during the welding process between the electrode tab and the copper foil, the root of the electrode tab will bend, which may cause micro-cracks, wrinkles and cracks on the contact surface between the electrode tab adhesive and the aluminum-plastic film, affecting the sealing performance. In particular, when the thickness of the electrode tab adhesive increases, the possibility of gaps appearing between the aluminum-plastic film and the electrode tab adhesive will greatly increase.

[0006] Therefore, it is necessary to propose a new technical solution to address the above problems. Utility Model Content

[0007] To overcome the shortcomings mentioned above, this utility model aims to provide a technical solution that can solve the aforementioned problems.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a lithium battery pack with an improved tab packaging position, comprising a battery cell, wherein the battery cell is wrapped with a protective film, one end of the protective film has a packaging edge, and a tab is packaged on the packaging edge;

[0009] The tab includes an aluminum strip that is electrically connected to the battery cell. A nickel strip is welded to one end of the aluminum strip, so that an overlapping area is formed at the welding point of the aluminum strip and the nickel strip. A layer of tab adhesive is wrapped on each side of the outer side of the overlapping area, and the two layers of tab adhesive are bonded to each other.

[0010] The encapsulation edge is also provided with an upper clamping plate and a lower clamping plate, which are respectively located on both sides of the encapsulation edge and are spliced ​​together to apply clamping force to the encapsulation edge.

[0011] As a further embodiment of this utility model: an upper fixing part is provided on one side of the upper clamping plate near the edge of the encapsulation, and a lower fixing part corresponding to the upper fixing part is provided on one side of the lower clamping plate, and the upper fixing part and the lower fixing part are bonded and fixed to each other.

[0012] The upper fixing part and the lower fixing part are located between the two pole ears.

[0013] As a further embodiment of this utility model: elastic layers are provided on both sides of the upper clamping plate and the lower clamping plate, and gaskets are provided on the elastic layers, with the gaskets fitting together with the sealing edge.

[0014] As a further embodiment of this utility model: the upper clamping plate, the lower clamping plate, and the gasket are all made of high-temperature resistant plastic.

[0015] As a further embodiment of this invention, the elastic layer is made of silicone.

[0016] As a further embodiment of this utility model: the upper fixing part has two slots on the side facing the lower fixing part, forming an "E" shaped structure, and the lower fixing part is provided with a plug that can be inserted into the two slots.

[0017] Compared with the existing technology, the beneficial effects of this technical solution are as follows: the overlapping area of ​​the aluminum strip and the nickel strip is wrapped with two layers of tab adhesive. When the tab is packaged, the tab adhesive is sandwiched inside the interlayer of the packaging edge and undergoes heat fusion to bond and fix it to the packaging edge. By wrapping the overlapping area generated by welding the aluminum strip and the nickel strip with two layers of tab adhesive, the defects caused by the stepped structure of the overlapping area are perfectly solved, such as the protective film being punctured and the electrolyte leaking.

[0018] The upper and lower clamps are placed on both sides of the encapsulation edge and spliced ​​together. During the splicing process, the upper and lower clamps apply clamping force to the encapsulation edge, making the encapsulation edge tighter and improving the tightness between the encapsulation edge and the tab adhesive, thereby further strengthening the sealing of the encapsulation edge and preventing electrolyte leakage.

[0019] The clamping of the upper and lower clamps ensures that when the tab is bent, the tab adhesive and the encapsulation edge will not interact. In other words, when the tab adhesive moves, it will move the encapsulation edge together, thus preventing micro-cracks and wrinkles from forming on the contact surface between the tab adhesive and the encapsulation edge due to bending, and preventing any impact on the sealing performance.

[0020] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 This is a cross-sectional structural diagram of the electrode tab of this utility model;

[0024] Figure 3 This is a schematic diagram of the structure of the upper and lower clamping plates of this utility model;

[0025] The corresponding labels in the attached diagram are explained as follows:

[0026] 1. Battery cell; 2. Protective film; 21. Encapsulation edge; 3. Electrode tab; 31. Aluminum strip; 32. Nickel strip; 33. Overlapping area; 34. Electrode tab adhesive; 4. Upper clamping plate; 41. Upper fixing part; 42. Slot; 5. Lower clamping plate; 51. Lower fixing part; 52. Insert post; 6. Elastic layer; 7. Gasket. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] Please see Figure 1-3 A lithium battery pack with improved tab packaging position includes a cell 1, the cell 1 is wrapped with a protective film 2, one end of the protective film 2 has a packaging edge 21, and a tab 3 is packaged on the packaging edge 21.

[0029] The tab 3 includes an aluminum strip 31 that is electrically connected to the battery cell 1. A nickel strip 32 is welded to one end of the aluminum strip 31, so that an overlapping area 33 is formed at the welding point of the aluminum strip 31 and the nickel strip 32. A layer of tab adhesive 34 is wrapped on both sides of the overlapping area 33, and the two layers of tab adhesive 34 are bonded to each other.

[0030] The encapsulation edge 21 is also provided with an upper clamping plate 4 and a lower clamping plate 5. The upper clamping plate 4 and the lower clamping plate 5 are respectively located on both sides of the encapsulation edge 21 and are spliced ​​together to apply clamping force to the encapsulation edge 21.

[0031] Specifically, the protective film 2 is an aluminum-plastic film, which wraps the battery cell 1 and overlaps at one end to form an encapsulation edge 21. The tab 3 is then encapsulated in the interlayer. The aluminum strip 31 of the tab 3 is responsible for connecting the battery cell 1. One end of the nickel strip 32 overlaps with the aluminum strip 31 and is fixed by laser welding. Then, two layers of tab adhesive 34 are used to wrap the overlapping area 33 of the aluminum strip 31 and the nickel strip 32. When encapsulating the tab 3, the tab adhesive 34 is sandwiched inside the interlayer of the encapsulation edge 21 and undergoes heat fusion to bond and fix it to the encapsulation edge 21. By wrapping the overlapping area 33 formed by welding the aluminum strip 31 and the nickel strip 32 with two layers of tab adhesive 34, the defects caused by the stepped structure of the overlapping area 33 are perfectly solved, such as the protective film being punctured and the electrolyte leaking.

[0032] Meanwhile, after the two tabs 3 are encapsulated, the upper clamping plate 4 and the lower clamping plate 5 are placed on both sides of the encapsulation edge 21 and spliced ​​together. During the splicing process, the upper clamping plate 4 and the lower clamping plate 5 will apply clamping force to the encapsulation edge 21, making the encapsulation edge 21 tighter and improving the tightness between the encapsulation edge 21 and the tab adhesive 34 of the tab 3, so as to further enhance the sealing of the encapsulation edge 21 and avoid electrolyte leakage.

[0033] The clamping of the upper clamping plate 4 and the lower clamping plate 5 ensures that when the tab 3 is bent, the tab adhesive 34 and the encapsulation edge 21 will not generate mutual force. That is, when the tab adhesive 34 moves, it will drive the encapsulation edge 21 together, thereby avoiding the formation of micro-cracks and wrinkles on the contact surface between the tab adhesive 34 and the encapsulation edge 21 due to bending, thus preventing the sealing performance from being affected.

[0034] Furthermore, an upper fixing part 41 is provided on the side of the upper clamping plate 4 near the edge of the encapsulation edge 21, and a lower fixing part 51 corresponding to the upper fixing part 41 is provided on one side of the lower clamping plate 5, and the upper fixing part 41 and the lower fixing part 51 are bonded and fixed to each other.

[0035] The upper fixing part 41 and the lower fixing part 51 are located between the two pole ears 3.

[0036] Specifically, when the upper clamping plate 4 and the lower clamping plate 5 are clamped on both sides of the encapsulation edge 21, the upper fixing part 41 and the lower fixing part 51 are pre-applied with glue on opposite sides and then bonded together to fix the upper clamping plate 4 and the lower clamping plate 5. The upper clamping plate 4 and the lower clamping plate 5 are fixed on the encapsulation edge 21 by using the clamping force between them.

[0037] Meanwhile, the upper fixing part 41 and the lower fixing part 51 are positioned between the two electrode tabs 3, thereby providing a fixing effect without affecting the welding of the two electrode tabs 3.

[0038] Furthermore, elastic layers 6 are provided on both sides of the upper clamping plate 4 and the lower clamping plate 5, and gaskets 7 are provided on the elastic layers 6, with the gaskets 7 fitting together with the encapsulation edge 21.

[0039] Specifically, after the upper clamping plate 4 and the lower clamping plate 5 are spliced ​​and fixed together, the distance between them will be slightly smaller than the encapsulation edge 21 and the thickness. This means that when the upper clamping plate 4 and the lower clamping plate 5 are spliced ​​together to clamp the encapsulation edge 21, the elastic layer 6 is subjected to a certain degree of compression. After the elastic layer 6 deforms, it will generate an elastic restoring force that acts on the encapsulation edge 21. Under the interaction of the two elastic layers 6, the clamping force on the encapsulation edge 21 can be further improved. Moreover, the force applied by the elastic layer 6 is relatively gentle. While clamping the encapsulation edge 21, it can also protect the encapsulation edge 21. The gasket 7 is tightly attached to the encapsulation edge 21 and is made of high-temperature resistant plastic (such as polyamide PA, polyetheretherketone PEEK). While ensuring insulation, it prevents the battery pack from melting when it heats up. In addition, the upper clamping plate 4 and the lower clamping plate 5 are also made of high-temperature resistant plastic (such as polyamide PA, polyetheretherketone PEEK).

[0040] Among them, the elastic layer 6 is made of silicone. Silicone has excellent deformation properties, which meets the usage requirements and can also play a role in shock absorption.

[0041] Furthermore, the elastic layer 6 and the gasket 7 are bonded together and then the elastic layer 6 is bonded to the upper clamping plate 4, thereby fixing the elastic layer 6 and the gasket 7 on the upper clamping plate 4. The elastic layer and the gasket 7 are also fixed on the lower clamping plate 5 by bonding.

[0042] Furthermore, the upper fixing part 41 has two slots 42 on the side facing the lower fixing part 51, forming an "E" shaped structure, and the lower fixing part 51 is provided with a plug 52 that can be inserted into the two slots 42.

[0043] Specifically, when bonding the upper fixing part 41 and the lower fixing part 51, the insertion post 52 and the slot 42 are interlocked, which can increase the contact area between the upper fixing part 41 and the lower fixing part 51, making the bonding effect better. In addition, the interlocking of the insertion post 52 and the slot 42 also provides an anti-displacement effect.

[0044] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A lithium battery pack with improved tab packaging position, characterized in that, Includes a battery cell (1), the battery cell (1) is wrapped with a protective film (2), one end of the protective film (2) has an encapsulation edge (21), and a tab (3) is encapsulated on the encapsulation edge (21). The tab (3) includes an aluminum strip (31) electrically connected to the battery cell (1). A nickel strip (32) is welded to one end of the aluminum strip (31), so that an overlapping area (33) is formed at the welding point of the aluminum strip (31) and the nickel strip (32). A layer of tab adhesive (34) is wrapped on each side of the outer side of the overlapping area (33), and the two layers of tab adhesive (34) are bonded to each other. The encapsulation edge (21) is also provided with an upper clamping plate (4) and a lower clamping plate (5). The upper clamping plate (4) and the lower clamping plate (5) are respectively located on both sides of the encapsulation edge (21) and are spliced ​​together to apply clamping force to the encapsulation edge (21).

2. The lithium battery pack with improved tab packaging position according to claim 1, characterized in that, The upper clamping plate (4) has an upper fixing part (41) on one side near the edge of the encapsulation edge (21), and the lower clamping plate (5) has a lower fixing part (51) on one side corresponding to the upper fixing part (41), and the upper fixing part (41) and the lower fixing part (51) are bonded and fixed to each other. The upper fixing part (41) and the lower fixing part (51) are located between the two tabs (3).

3. The lithium battery pack with improved tab packaging position according to claim 2, characterized in that, The upper clamping plate (4) and the lower clamping plate (5) are provided with elastic layers (6) on opposite sides. The elastic layers (6) are provided with gaskets (7), and the gaskets (7) are in contact with the encapsulation edge (21).

4. The lithium battery pack with improved tab packaging position according to claim 3, characterized in that, The upper clamping plate (4), lower clamping plate (5) and gasket (7) are all made of high-temperature resistant plastic.

5. The lithium battery pack with improved tab packaging position according to claim 3, characterized in that, The elastic layer (6) is made of silicone.

6. The lithium battery pack with improved tab packaging position according to claim 2, characterized in that, The upper fixing part (41) has two slots (42) on the side facing the lower fixing part (51) to form an "E" shaped structure. The lower fixing part (51) is provided with a plug (52) that can be inserted into the two slots (42).

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